If your friend has a problem staying away from gambling and his casino work is leading him astray, he should find another job.
Good point and a great suggestion, but in countries like ours, there aren't enough jobs for the youths, so there's little or no guarantee for him to getting another job within the closest time frame, hence I didn't go that route since I don't have one for him myself.
Another truth is that dude's happy with his job, he enjoys his daily activities at the casino, he only needed help with excessive gambling and I provided assistance in that direction. Persuading him to quit the job outrightly without offering him a new one or financial support while he searches for a new one might look as though I want to render him jobless and he might even see me as an enemy of progress.
If that is the case, you can suggest your friend to learn about controlling himself so he can stay away from the wanting of playing gambling. Working at casino have a big temptation to join with the other gamblers to win the games because he will see some gamblers can win some money by playing the gambling games. But he must realizes that if he really want to still playing gambling after he free from his job, he must have a strong self control to avoids from spending much money.
He must remember that he must fills his daily needs so he can still aware that he playing gambling to release his stress of his job. You can be besides of him after he end his job at that day and if he wants to playing gambling, you can watch him playing gambling and reminds him if he almost break his limitation. It needs a strong self controls to say it is enough to playing gambling for this day but I am sure he can do that and you can helps him to solve his problem.